The present invention relates to a thin film transistor liquid crystal display and a manufacturing method thereof.
Thin film transistor liquid crystal displays (TFT-LCDs) have the advantages of small volume, low power consumption, no radiation and so on and is becoming dominant in the current planar panel display market.
A traditional TFT-LCD comprises an array substrate, a color filter substrate, and liquid crystal material filled between the two substrates. The displaying mechanism of a TFT-LCD is that the electric field formed between the color filter substrate and the array substrate renders the liquid crystal molecules orientated, and the twisting angle of the liquid crystal molecules can be controlled by the electric field, intensity of which is adjusted by varying the applied voltage, so that the amount of light transmitted through pixels can be controlled and the desired image can be obtained. The array substrate comprises gate lines, data lines, pixel electrodes, and thin film transistors formed on a base substrate such as a glass substrate. The color filter substrate comprises a black matrix, red, green and blue (RGB) color resins, and a layer of indium tin oxide (ITO). The RGB color resins are used to achieve the color display of the liquid crystal display, the ITO layer is used for providing a common electrode for the color filter substrate, and the black matrix is used to shield the pixel peripheral area and the irregularly aligned liquid crystal molecules in a TFT forming area.
The traditional manufacturing process of a TFT-LCD mainly comprises a color filter process, an array process, and an assembling process. In the color filter process, the color filter substrate is prepared by repeating several times of film deposition, photolithograph, etching and the like on a glass substrate. Similarly, in the array substrate, the array substrate is prepared by repeating several times of film deposition, photolithograph, etching and the like on another glass substrate. In the assembling process, the prepared color filter substrate and array substrate are combined to form a liquid crystal display panel of a certain size by a serial of processes of alignment film applying, rubbing, liquid crystal filling, bonding, cutting, and the like.
In the traditional manufacturing process of a TFT-LCD, since the bonding deflection within a certain range arises in the assembling process of the color filter substrate and the array substrate, the product quality is disadvantageously affected to some extent. Where the deflection goes beyond the well-established standard, not only the black matrix cannot function properly to shield light, but also the displacement of the RGB color resins occurs, resulting in bad image quality. Even if the bonding deflection falls into an allowable range, the displacement of the color filter and the array substrate occurs upon a flapping test, which gives rise to white area in a normal image and results in image displaying defect. According to the traditional process, the bonding deflection can only be controlled within about 7.0 μm. Therefore, in order to prevent the poor light shield of the black matrix due to the bonding deflection, the traditional process normally appropriately enlarges the shielding area of the black matrix; however, the aperture ratio of a pixel unit is degraded.